Powdery mildew of tomato is caused by -

Correct option is A

· Correct answer: (a) Erysiphe cichoracearum
· Erysiphe cichoracearum is the pathogen that causes powdery mildew on tomatoes. This fungal disease is characterized by white, powdery fungal growth on the leaves, leading to reduced photosynthesis.
Other options:
· (b) Erysiphe polygoni: Affects other plants, not tomatoes.
· (c) Erysiphe betae: Affects beets, not tomatoes.
· (d) Erysiphe orontii: Another powdery mildew pathogen, but not the cause of tomato mildew.